How to package org.eclipse.swt into the project jar

I created a Maven project in which I used SWT as the UI of the program. But when I package the project, an error occurs, which prevents me from packaging the additional jar files I referenced into my project jar.

error message: [WARNING] The POM for org.eclipse.platform:org.eclipse.swt:jar:3.127.0 is invalid, transitive dependencies (if any) will not be available: 1 problem was encountered while building the effective model for org.eclipse.platform:org.eclipse.swt:3.127.0 [ERROR] 'dependencies.dependency.artifactId' for org.eclipse.platform:org.eclipse.swt.${osgi.platform}:jar with value 'org.eclipse.swt.${osgi.platform}' does not match a valid id pattern. @

original dependency

<dependency>
    <groupId>org.eclipse.platform</groupId>
    <artifactId>org.eclipse.swt.win32.win32.x86_64</artifactId>
    <version>3.127.0</version>
</dependency>

I referred to this article (https://www.vogella.com/tutorials/SWT/article.html#exercise-using-the-swt-library-in-a-maven-project)

Create a lib folder in the project, put the jar in, and then set the dependency

<dependency>
    <groupId>org.eclipse.platform</groupId>
    <artifactId>org.eclipse.swt</artifactId>
    <version>1.0.0</version>
    <scope>system</scope>
    <systemPath>${basedir}/lib/swt.jar</systemPath>
</dependency>

I use absolute path for systemPath.

But when packaging, there is no way to package swt into jar.

In the plugin, I also set the maven-assembly-plugin.

<plugin>
  <artifactId>maven-jar-plugin</artifactId>
  <version>3.4.2</version>
  <configuration>
    <archive>
        <manifest>
            <mainClass>cc.demo.SwtDemo.App</mainClass>
        </manifest>
    </archive>
   </configuration>
</plugin>
<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-assembly-plugin</artifactId>
  <version>3.7.0</version>
  <executions>
    <execution>
      <phase>package</phase>
      <goals>
        <goal>single</goal>
      </goals>
    </execution>
  </executions>
  <configuration>
    <descriptorRefs>
      <descriptorRef>jar-with-dependencies</descriptorRef>
    </descriptorRefs>
    <archive>
        <mainClass>cc.demo.SwtDemo.App</mainClass>
    </archive>
  </configuration>
</plugin>

When I run the output jar, I will encounter Exception.

Exception in thread "main" java.lang.NoClassDefFoundError: org/eclipse/swt/widgets/Layout at cc.derick.YouTubeMemberEmojiDownloader.App.main(App.java:11) Caused by: java.lang.ClassNotFoundException: org.eclipse.swt.widgets.Layout at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:641) at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:188) at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:526) ... 1 more

I tried using the Maven Build tool inside Eclispe I also tried issuing the mvn clean package command on the terminal. The result is the same.

Solution

Swt requires different packages according to different OS.
Use different Profiles to set the variables swt.groupId, swt.artifactId, and swt.version corresponding to the dependency's groupId, artifactId, and version.
Or you can hard code the swt artifactId and version of SWT corresponding to the OS platform you are currently developing into the dependency.

maven pom.xml

...

<plugin>
  <artifactId>maven-jar-plugin</artifactId>
  <version>3.4.2</version>
  <configuration>
    <archive>
      <manifest>
        <addClasspath>true</addClasspath>
        <mainClass>cc.demo.SwtDemo.App</mainClass>
      </manifest>
      <manifestEntries>
        <built-by />
        <!-- add empty for not add user name -->
        <Class-Path>.</Class-Path>
        <App-Version>${project.version}</App-Version>
      </manifestEntries>
    </archive>
  </configuration>
</plugin>


<plugin>
  <groupId>org.codehaus.mojo</groupId>
  <artifactId>appassembler-maven-plugin</artifactId>
  <version>2.1.0</version>
  <executions>
    <execution>
      <phase>package</phase>
      <goals>
        <goal>assemble</goal>
      </goals>
    </execution>
  </executions>
  <configuration>
    <programs>
      <program>
        <mainClass>cc.demo.SwtDemo.App</mainClass>
        <id>SwtDemo.App</id>
      </program>
    </programs>
    <extraJvmArguments>
-Duser.language=en
-Duser.country=US
-Dfile.encoding=UTF-8
-Xms128M
-Xmx756M
    </extraJvmArguments>
    <repositoryLayout>flat</repositoryLayout>
    <useWildcardClassPath>true</useWildcardClassPath>
    <binFileExtensions>
      <!--<unix>.sh</unix> -->
    </binFileExtensions>
    <repositoryName>lib</repositoryName>
  </configuration>
</plugin>

...

<dependencies>
  <dependency>
    <groupId>${swt.groupId}</groupId>
    <artifactId>${swt.artifactId}</artifactId>
    <version>${swt.version}</version>
  </dependency>
</dependencies>

<profiles>

  <!-- Linux -->
  <profile>
    <id>linux</id>
    <activation>
      <os>
        <name>Linux</name>
        <arch>amd64</arch>
      </os>
    </activation>
  <properties>
    <swt.groupId>org.eclipse.platform</swt.groupId>
    <swt.artifactId>org.eclipse.swt.gtk.linux.x86_64</swt.artifactId>
    <swt.version>3.119.0</swt.version>
  </properties>
  </profile>

  <!-- Windows -->
  <profile>  
    <id>windows</id>
    <activation>
      <os>
        <name>Windows 10</name>
        <arch>amd64</arch>
      </os>
    </activation>
    <properties>
      <swt.groupId>org.eclipse.platform</swt.groupId>
      <swt.artifactId>org.eclipse.swt.win32.win32.x86_64</swt.artifactId>
      <swt.version>3.119.0</swt.version>
    </properties>
  </profile>
  
  <!-- MacOSX -->
  <profile>
    <id>macosx</id>
    <activation>
      <os>
        <name>Mac OS X</name>
        <arch>x86_64</arch>
      </os>
    </activation>
    <properties>
      <swt.groupId>org.eclipse.platform</swt.groupId>
      <swt.artifactId>org.eclipse.swt.cocoa.macosx.x86_64</swt.artifactId>
      <swt.version>3.119.0</swt.version>
    </properties>
  </profile>
</profiles>

<repositories>
  <!-- add for swt -->
  <repository>
    <id>repo1</id>
    <name>repo1</name>
    <url>https://repo1.maven.org/maven2</url>
  </repository>
</repositories>